we still use a simple text field for naming custom fields, while this is a
special field which should not contain spaces or special chars. Do you plan
to change this, or is there a way to call the custom field ID instead of its
name?

cust_LinkCountry is made of cust_ + custom field name, that's why I ask
propose to eliminate this source of problem. It's a not a big deal now, but
the more users we'll have, the more case they'll report on something which
"appears" like a bug, but is not at all.